As mobile low-power devices such as tablets and smart phones become more popular playback devices for protected audio/video content such as encrypted video, music and the like, it becomes more important to provide power-efficient audio/video processing solutions such as high quality video playback and video conferencing. Video playback and video conferencing solutions need content security so that, e.g., malicious software is not able to access, copy, or otherwise steal the content.
A variety of encryption schemes are commercially available to secure the content, for example the Advanced Encryption Standard (AES), promulgated by the National Institute of Standards and Technology (NIST) as Federal Information Processing Standards Publication 197, Nov. 26, 2001. AES is a symmetric encryption scheme, such that a same cipher key is used for both encoding and decoding. The AES scheme itself exists in multiple variations, such as AES counter mode, AES cipher block chaining (CBC)+cipher text stealing (CTS), RSA, and so forth. Some variations of AES may be described in Request for Comment (RFC) 3962, “Advanced Encryption Standard (AES) Encryption for Kerberos 5,” February 2005, and references cited therein. The variety of encryption schemes impose different limitations on encryption and decryption implementations. The limitations affect video processing pipelines, which include hardware modules. Accordingly, a need exists for more flexible encryption scheme implementations for low-power devices.